package org.gavin.core.utils;

import lombok.extern.slf4j.Slf4j;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.pqc.math.linearalgebra.ByteUtils;
import org.gavin.core.enums.CommonStatus;
import org.gavin.core.exception.DataException;
import org.springframework.util.DigestUtils;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.Key;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Arrays;

/***
 * 国密算法SM4-对称加密
 * @author gangwei.chen
 * @version V1.0.0
 * @date 2022-10-12 08:57:49
 */
@Slf4j
public class GMSM4Utils {
    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    private static final String ENCODING = "UTF-8";
    public static final String ALGORITHM_NAME = "SM4";
    /**
     *    加密算法/分组加密模式/分组填充方式
     *    PKCS5Padding-以8个字节为一组进行分组加密
     *    定义分组加密模式使用：PKCS5Padding
     */
    public static final String ALGORITHM_NAME_ECB_PADDING = "SM4/ECB/PKCS5Padding";
    /**
     * 128-32位16进制；256-64位16进制
     */
    public static final int DEFAULT_KEY_SIZE = 128;

    /**
     * 生成ECB暗号
     *
     * @param algorithmName 算法名称
     * @param mode          模式
     * @param key
     * @return
     * @throws Exception
     * @explain ECB模式（电子密码本模式：Electronic codebook）
     */
    private static Cipher generateEcbCipher(String algorithmName, int mode, byte[] key) throws Exception {
        Cipher cipher = Cipher.getInstance(algorithmName, BouncyCastleProvider.PROVIDER_NAME);
        Key sm4Key = new SecretKeySpec(key, ALGORITHM_NAME);
        cipher.init(mode, sm4Key);
        return cipher;
    }

    /**
     * 自动生成密钥
     *
     * @return
     * @explain
     */
    public static byte[] generateKey() throws Exception {
        return generateKey(DEFAULT_KEY_SIZE);
    }

    /**
     * @param keySize
     * @return
     * @throws Exception
     * @explain 系统产生秘钥
     */
    public static byte[] generateKey(int keySize) throws Exception {
        KeyGenerator kg = KeyGenerator.getInstance(ALGORITHM_NAME, BouncyCastleProvider.PROVIDER_NAME);
        kg.init(keySize, new SecureRandom());
        return kg.generateKey().getEncoded();
    }

    /**
     * @return
     * @throws Exception
     * @explain 系统产生秘钥
     */
    public static String generKey() throws Exception {
        return ByteUtils.toHexString(generateKey()).toUpperCase();
    }

    /**
     * sm4加密
     *
     * @param hexKey   16进制密钥（忽略大小写）
     * @param paramStr 待加密字符串
     * @return 返回16进制的加密字符串
     * @throws Exception
     * @explain 加密模式：ECB 密文长度不固定，会随着被加密字符串长度的变化而变化
     */
    public static String encryptEcb(String paramStr, String hexKey) {
        try {
            String cipherText = "";
            // 16进制字符串-->byte[]
            byte[] keyData = ByteUtils.fromHexString(hexKey);
            // String-->byte[]
            byte[] srcData = paramStr.getBytes(ENCODING);
            // 加密后的数组
            byte[] cipherArray = encrypt_Ecb_Padding(keyData, srcData);
            // byte[]-->hexString
            cipherText = ByteUtils.toHexString(cipherArray);
            return cipherText;
        } catch (Exception e) {
            e.printStackTrace();
            log.error(e.getMessage(), e);
            throw DataException.le(CommonStatus.CIPHERTEXT_HANDLE_FAILED);
        }
    }

    /**
     * 加密模式之Ecb
     *
     * @param key
     * @param data
     * @return
     * @throws Exception
     */
    public static byte[] encrypt_Ecb_Padding(byte[] key, byte[] data) throws Exception {
        // 声称Ecb暗号,通过第二个参数判断加密还是解密
        Cipher cipher = generateEcbCipher(ALGORITHM_NAME_ECB_PADDING, Cipher.ENCRYPT_MODE, key);
        return cipher.doFinal(data);
    }

    /**
     * sm4解密
     *
     * @param hexKey     16进制密钥
     * @param cipherText 16进制的加密字符串（忽略大小写）
     * @return 解密后的字符串
     * @throws Exception
     * @explain 解密模式：采用ECB
     */
    public static String decryptEcb(String cipherText, String hexKey) {
        try {
            // 用于接收解密后的字符串
            String decryptStr = "";
            // hexString-->byte[]
            byte[] keyData = ByteUtils.fromHexString(hexKey);
            // hexString-->byte[]
            byte[] cipherData = ByteUtils.fromHexString(cipherText);
            // 解密
            byte[] srcData = decrypt_Ecb_Padding(keyData, cipherData);
            // byte[]-->String
            decryptStr = new String(srcData, ENCODING);
            return decryptStr;
        } catch (Exception e) {
            e.printStackTrace();
            log.error(e.getMessage(), e);
            throw DataException.le(CommonStatus.CIPHERTEXT_HANDLE_FAILED);
        }
    }

    /**
     * 解密
     *
     * @param key
     * @param cipherText
     * @return
     * @throws Exception
     * @explain
     */
    public static byte[] decrypt_Ecb_Padding(byte[] key, byte[] cipherText) throws Exception {
        Cipher cipher = generateEcbCipher(ALGORITHM_NAME_ECB_PADDING, Cipher.DECRYPT_MODE, key);// 生成Ecb暗号,通过第二个参数判断加密还是解密
        return cipher.doFinal(cipherText);
    }

    /**
     * 校验加密前后的字符串是否为同一数据
     *
     * @param hexKey     16进制密钥（忽略大小写）
     * @param cipherText 16进制加密后的字符串
     * @param paramStr   加密前的字符串
     * @return 是否为同一数据
     * @throws Exception
     * @explain
     */
    public static boolean verifyEcb(String hexKey, String cipherText, String paramStr) throws Exception {
        // 用于接收校验结果
        boolean flag = false;
        // hexString-->byte[]
        byte[] keyData = ByteUtils.fromHexString(hexKey);
        // 将16进制字符串转换成数组
        byte[] cipherData = ByteUtils.fromHexString(cipherText);
        // 解密
        byte[] decryptData = decrypt_Ecb_Padding(keyData, cipherData);
        // 将原字符串转换成byte[]
        byte[] srcData = paramStr.getBytes(ENCODING);
        // 判断2个数组是否一致
        flag = Arrays.equals(decryptData, srcData);
        return flag;
    }




    public static void main(String[] args) throws Exception {
        String s = generKey();
        System.out.println("----generKey-------"+s);
        String body = "@jKdbip&3788dd8*!$*";
        String secret = "149754AD034EE1C319C7A6601B3E97E0";
        String uniqueValue = "9ef62c34ca4e4e6d81ef5c6268c593e6"+System.currentTimeMillis();
        System.out.println("-----uniqueValue------"+uniqueValue);
        String decSecret = DigestUtils.md5DigestAsHex((secret + uniqueValue).getBytes(StandardCharsets.UTF_8));
        String param = GMSM4Utils.encryptEcb(body, decSecret);
        System.out.println("加密后：" + param);
/*
        String encSecret = "B88757F2396BCA91F677FBB1C97A6F8B";
        String resultData = "ab84eb276349cdac338751873fc96f9dae15fca61eb43c7764009d4a4efc6e2e80baac9baecd757df64f645ec19c43ed";
        String encSecretKey = DigestUtils.md5DigestAsHex((encSecret + "9ef62c34ca4e4e6d81ef5c6268c593e61713855019890").getBytes(StandardCharsets.UTF_8));
        String result = GMSM4Utils.decryptEcb(resultData, encSecretKey);
        System.out.println("解密后：" + result);*/

    }

}
